Anchoring device

ABSTRACT

A helically convoluted spring sleeve of soft wire is insertable into a bore hole. An expander member has one part located forwardly of the leading end of the sleeve, and another part located in the leading end and tapering towards the trailing end of the sleeve. A cap sleeve has one section located outside and in abutment with the trailing end of the sleeve, and another part located within the trailing end. An expanding screw extends through a central passage of the expanding sleeve and through the spring sleeve into engagement with the expander member so that the latter can be drawn into the spring sleeve for radially expanding the same.

United States Patent .1191

Fischer 1 Sept. 24, 1974 1 ANCHORING DEVICE 3,202,034 8/1965 Korenchan85/75 Inventor: Artur Fischer, Altheimer Strasse 3,313,200 4/1967Fischer 85/75 219 13-7241 Tumlingen, Germany FOREIGN PATENTS ORAPPLICATIONS 79,321 11/1951 Norway 85/64 [22] 1972 128,326, /1956 Sweden[21] Appl, No; 280,885 249,955 /1966 Austria 1,022,013 3/1966 GreatBritain 85/64 Foreign Application Priority Data Primary Examiner-EdwardC. Allen Aug. 17, 1971 Germany 2141079 Attorney, Agent, or FirmMichaelS. Striker Sept. 14, 1971 Germany 2145918 Dec. 15, 1971 Germany 2162255[57] ABSTRACT Dec. 14, 1971 Germany 2164587 A convoluted p g sleeve ofSoft wire is sertable into a bore hole. An expander member has [52] US.Cl 85/64, 85/67, 85/73 one part located forwardly of the leading end ofthe F161) Sleeve, and another p located in the leading end [58] d 0Search 85/64 75 and tapering towards the trailing end of the sleeve. A 6R f cap sleeve has one section located outside and in abut- [5 1 eerences C'ted ment with the trailing end of the sleeve, and anotherUNITED STATES PATENTS part located within the trailing end. An expanding570,786 11/1896 Church /67 screw extends through a central passage ofthe ex- 768,283 8/1904 Jenkins 85/64 panding sleeve and through thespring sleeve into en- 1,120,409 12/1914 1101111161! et a1. 85/67gagement the expander member so that the latter g; i acan be drawn intothe spring sleeve for radially exenne y 1,395,453 11/1921 Peirce 85/74pandmg the Same 1,852,297 4/1932 Gelpeke 85/67 15 Claims, 9 DrawingFigures Ito.

f 0':- J 9 jia .f Q 9 t O PATENTEDSEPM 1w ales-r257 SHEET 38$ 4ANCHORING DEVICE BACKGROUND OF THE lNVENTlON The present inventionrelates to an anchoring device for fastening in a drill or bore holeformed in concrete construction components.

When testing a known device of this kind, it has been found that afastening effect which resists large extraction forces could not beachieved. That device usesan expansible helical spring and it was found,surprisingly, that spring coils in the zone of the conical expansionbody overlap during axial tensioning and are strongly pressed into thewall of the drill hole. Consequently, the fastening action wasrestricted to two, but in most cases to only one coil. Moreover, when anextraction force was applied in direction axially of the hole, the coilthat was pushed against the wall of the drill hole slid over theexpansion body, so that the expansion body was inserted into the springpast the tensioned coil. No tensioning of the spring coils could beachieved in the zone of the mouth of the drill hole which, as is known,is often both larger than the desired diameter and not circular.

SUMMARY OF THE INVENTION It is a general object of the invention toprovide an anchoring device of the kind described above, that permitsthe application of large extraction forces in concrete constructionelements without damage to the wall.

A further object of the invention is to provide such a device which canbe manufactured very simply and economically.

Another object of the invention is to provide such de- A vice whichachieves, with only a single spring sleeve, an effective fastening overthat region of the spring upon which the expansion body or member of thedevice acts.

This is achieved, according to one feature of the invention, by windingthe spring sleeve as a block spring, providing the expansion body at itsinsertion end with a collar, the outside diameter of which correspondsto the diameter of the drill hole, and arranging at the trailing end ofthe spring sleeve opposite the insertion or leading end thereof a caphaving two sections, one section protruding into the spring sleeve andthe other section covering the front face of the latter.

To fasten the device according to the invention, a bore or drill hole isfirst produced in a structure in which the device is to be anchored; thediameter of the bore corresponds to the outside diameter of the springsleeve. The device is now inserted into the drill hole together with theexpansion body and with the fixing or expanding screw, a few threads ofwhich have been screwed into the expansion body. In hard concrete it ishardly possible to produce a perfectly cylindrical hole. Due to itselasticity the spring sleeve, however, adapts itself to the wall of thedrill hole and thus achieves, before the expansion body has beeninserted, a'bracing action which is sufficient to prevent the twistingof the device in the drill hole when the expansion body is inserted. Atthe same time, the coils of the spring sleeve at the leading end thereofalso exert a bracing action upon the expansion body, so that the lattercannot twist in relation to the spring sleeve when the fixing screw issubsequently turned.

During insertion'of the device into the drill hole, some of theconvolutions of the spring sleeve are pushed radially outwards againstthe wall of the drill hole by the cone of the expansion body. At thesame time, the device is shortened due to axial contraction and radialexpansion of the sleeve, so that the remaining coils of the springsleeve overlap and are thus clamped into the space betweenfixing screwand the drill hole wall.

Only radial expansion forces are effective in the anchoring of thedevice according to the invention, and the expansion action and thepressure are uniformly distributed over a great length andcircumference, independent of uneven and irregular zones of the wall ofthe drill hole. Through this so-called soft fixing, locally increasedsurface pressures which destroy the concrete structure, are avoided, andchipping is eliminated, so that break-out cones are not formed in theconcrete.

It is a further advantageous effect of the spring sleeve of the noveldevice, that the expansion action increases with increasing extractionforce. Tests have even proved that after applying a first highextraction force, which was followed by a short displacement andsubsequent renewed engaging of the device in the drill hole, a highersecond extraction force could be applied and would not lead to theextraction of the device. This factor, which is essential for the safetyof the fastening action, thus meets a demand which is frequently madefor statics considerations.

Due to the uniform pressure distribution of the device and due to theabsence of a chipping action, a drill hole of small depth suffices foreffective fastening, for example for supporting components of suspendedceilings, tubes, or other elements.

In the device according to the invention, the spring sleeve in effect asa dowel sleeve and as an expansion sleeve,'that is as adowel body.Without impairing the function of the dowel, it is thus possible toshorten the length of the dowel by cutting the spring wire. It is thuspossible for the first time to adapt, by cutting its expansion sleeve, ametal dowel to any drill hole depth and to any purpose.

The cap serves for guiding the spring and, moreover, prevents jammingand tilting of the first coil or convolution at the trailing end of thespring sleeve in the bore of an object to be secured.

According to one embodiment of the invention, the spring sleeve may bewound from soft wire, in particular from copper wire. This facilitatesthe insertion of the expansion body into the spring sleeve, because asleeve of soft wire can be more easily expanded by the expansion body.

Advantageously, the spring sleeve may be wound right-handed. Due to itselasticity, the spring sleeve pushes against the cone of the expansionbody in such a manner that under normal conditions the expansion bodycannot twist in relation to the spring sleeve. If, however, twistingshould happen nevertheless, for example if the thread of the fixingscrew is damaged, the spring sleeve whose coils are in contact with theexpansion body, is also twisted in clockwise direction as the screw isrotated. In the case of right-handed winding of the spring sleeve,however, the latter will then contract and engage the expansion withincreasing pressure until the action which prevents twisting is againfully effective.

Further, the end of the wire at the insertion or leading end of thespring sleeve may be bent outwards. When the fixing screw is screwed in,this wire end engages with the wall of the drill hole and thus alsocontributes to the prevention of spring twist in relation to the drillhole.

According to another advantageous embodiment of the invention, theexpansion body may contain at its trailing end opposite its leading orinsertion end a cylindrical attachment or portion, the outside diameterof which corresponds to the inside diameter of the spring sleeve. Thisattachment serves for centering the expansion body in the spring sleeve.

According to a further concept of the invention, a collar that engagesin the coils of the spring sleeve may be arranged at the attachment.This collar is advantageously formed with a thread. The expansion bodycan thus be screwed into the spring sleeve without the possibility ofbeing lost, so that it is easily possible to unthread the fixing screwfrom the expansion body after the device according to the invention hasbeen anchored in the bore hole.

Finally, at least part of the outer surface of the attachment may beroughened, as for example by knurling. This construction increases thefriction between the spring sleeve and the expansion body still further,so that twisting of the expansion body in relation to the spring sleeveis excluded.

Without departing from the concept underlying the present invention, itis also possible to configurate the thread section of the fixing screwin such a manner that the outside diameter of the spring sleevecorresponds to the shaft diameter of the fixing screw.

This construction permits so-called push-through assembly, which savestime and expense because the bore holes in the basic support structureand in the element to be fastened to it, are formed simultaneously withthe element being in position on the support structure. Then the deviceis simply pushed from the exposed side of the element through the borehole thereof so as to extend partly into the bore hole of the supportstructure, andis thereupon anchored. In order to increase the expansioneffect, the end of the shaft of the fixing screw may in addition beconically tapered in the direction of the thread section, so that thespring is braced between the cones of the expansion body and the fixingscrew opposite one another.

In the same manner, the section of the cap that protrudes into thelongitudinal passage of the spring sleeve may be tapered in thedirection of the leading or insertion end.

The novel device thus comprises a spring sleeve and two opposed cones asexpansion bodies. bracing the spring sleeve in the drill hole. Thespring sleeve itself forms or acts as a dowel body that can be widened,i.e. radially expanded. By screwing in the fixing screw, the expansionbody is drawn towards the trailing end of the sleeve, i.e. in thedirection of the cap provided with a cone, which is supported by theobject to be fixed. The reduction of the gap between the two oppositecones effects an axial shortening of the spring, the coils of which thusundergo concomitant radial expansion and are pushed against the wall ofthe drill hole. Moreover, the two cones penetrate into the passage ofthe spring sleeve and further expand the latter. Two factors are thusessential for the fastening of the device, which by their cooperationcontribute to the achievement, by

means of the device according to the invention, of retention valueswhich far surpass those of known anchoring devices.

According to another advantageous embodiment of the invention, acylindrical attachment may be provided on the cone of the cap, theoutside diameter of which attachment corresponds to the inside diameterof the spring sleeve. This latter attachment serves for centering andguiding the spring sleeve.

A further embodiment provides for a collar which engages in the coils ofthe spring sleeve and which may be arranged at the attachment. By meansof this collar, the

cap is connected with the spring sleeve without the possibility of beinglost.

As a rule, the device is mounted flush with the wall. Since the outsidediameter of the fixing screw to be screwed into the expansion body issmaller than the outside diameter of the device per se, this means thatthe fixing screw is free in the object to be fixed. How ever, the objectto be fixed has thus no support, and the device also lacks a counterbearing when the expansion body is drawn in by means of the fixingscrew, due to the equality. of the drill hole diameters in the wall andin the object to be fixed, which counter bearing should of courseprevent the withdrawal of the device from the drill hole.

This is avoided according to another advantageous embodiment of theinvention by constructing the cap as a tubular element which extendsrearwardly beyond the trailing end of the spring sleeve.

Before the device according to the invention is fastened, a hole isdrilled into the wall through the object to be fixed, the diameter ofwhich hole corresponds to the outside diameter of the device. Withouthaving to remove the object to be fixed from the wall, the device maythen be inserted to such an extent that its upper end is flush with theouter surface of the object to be fixed (push-through installation). Bydrawing in the expansion bodyby means of a stay bolt and a nut, or,respectively, a cap screw, the device is then anchored fastened in thedrill hole and the object is secured to the wall.

In an advantageous embodiment, the rearwardly extended portion of thecap may be provided with a circumferential recess of saw-toothshapedcross section, and which has a distance from the trailing end of thedevice that preferably corresponds to the thickness of an object to befixed. The reduction in the wall thickness of the cap which is caused byprovision of this recess has the result that an upset occurs when thefixing screw is screwed in further, or the nut is tightened further,after the anchoring of the device in the zone of the change of thecross-section, which upset enables the object to be fixed to be bracedparticularly rigidly to the wall.

The recess has the further advantage. that the rear section which isseparated by this recess from the remainder of the cap can be readilyremoved when not needed. This is desirable when, for example, thethickness of the object to be fixed is small and the rear sectiontherefore not needed. In mass production it is expedient to restrict thespacing of the recess from the trailing end of the device to a fewselected distances. As

a rule, it will nevertheless be possible to readily find the selecteddistances may be compensated by inserting the device more deeply intothe bore hole.

The necessity of tightly drawing the anchored object against the surfaceof the concrete support structure or the like, once the device has beenanchored in the bore hole of the latter, by corresponding tightening ofthe nut or screw, pre-supposes a further penetration of the rearwardlyextended cap into the drill hole, because in the case of a push-throughassembly, as is known, the cap is in contact with the nut or the head ofthe fixing screw. This can be achieved by so constructing the springsleeve that over the major part of its length adjacent coils orconvolutions forming the spring sleeve are in the nonexpanded state ofthe sleeve in immediate contact with one another in the manner of ablock spring, while the remaining (trailing) part of the sleeve, whichfaces away from the expansion body, has its coils located at a distancefrom one another.

In this embodiment, the part of the spring sleeve which is wound in themanner of a block spring is first expanded by drawing in the cone bymeans of the fixing screw and is thus braced against the wall of thedrill hole.

The block spring-type part of the spring sleeve is already stationarilyfastened in thedrill hole by this bracing. When the expansion body isdrawn in still further, the fastening effect is further reinforced onthe one hand, while on the other hand the cap is now drawn forwardlyinto the drill hole to such an extent that those coils which werepreviously not in contact with one another will now move into suchabutment.

When this state has been reached, the anchoring of the device in thedrill hole, as well as the bracing of the object which is to be fixedbetween the head of a screw or the nut of a screw bolt and the surfaceof the structure in which the device is anchored are completed. Thedesired bracing of the object to be fixed can also be achieved byproviding the center passage of the extended cap with a short widenedbar section extending inwardly from its free rear end face.

This widened bore section results in the cap having in the zone of itsfree rear end face a region of reduced wall thickness, which can giveway after the anchoring of the device in the drill hole and when thefixing screw or the fixing nut are thereupon further tightened, so thatin this embodiment too, a bracing of the object to be fixed to thesurface of the support structure is made possible. The region of reducedwall thickness carries the further advantage that when a stay bolt withfixing nuts is used, and the drill hole has inadvertently been drilledoblique, complete contact of the fixing nut and the surface of theobject to be fixed can nevertheless be achieved. The region of reducedwall thickness will partially yield so that the nut can take up aposition perpendicular to the axis of the bore, the stay bolt beinggiven a slight deflection in that its end protruding from the bore holeis bent in the direction of the axis of the bore.

The retention values of the novel device can be increased still furtherif a better pressure distribution in the zone of the expansion body canbe achieved and, moreover, if sliding of the coils over expansion bodyis prevented when the latter is drawn in.

This is achieved by arranging between the cone and the collar of theexpansion body a cylindrical section with a diameter corresponding tothe largest diameter of the cone, the length of which cylindricalsection suffices for taking up at least one coil of the spring.

By means of the cylindrical section, the outside diameter of whichcorresponds to the largest diameter of the cone, several coils areexpanded to the same outside diameter, so that several coils are pressedwith maximum pressure against the wall of the drill hole. This resultsin further improvement of the pressure distribution, which increases theretention values. The collar at the leading or insertion end of theexpansion body, whose diameter corresponds to the inside diameter of thedrill hole, prevents a further sliding back of the spring sleeve, sothat the other coils too contribute to the fastening of the device bythe shortening of the spring sleeve. Two factors are thus essential forthe fastening, the cooperation of which makes the achievement of highextraction values possible.

The increase in the retention values of the device depends substantiallyupon the length of the cylindrical section. An increase may already beachieved if the section has a length which suffices for taking up onecoil. Tests have shown, however, that an optimum value of the increaseis achieved when the cylindrical section is given sufficient length topermit two to four coils to be taken up.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a device according to theinvention, inserted into a concrete support structure;

FIG. 2 illustrates a special construction of an expansion body;

FIG. 3 shows a device according to the invention in a differentembodiment, inserted into a concrete. sup-.

port structure;

FIG. 4 illustrates an embodiment permitting pushthrough assembly;

FIG. 5 shows a special construction of a cap;

FIG. 6 shows an embodiment of the device having a rearwardly extendedcap;

FIG. 7 illustrates a special construction of the free rear end of a cap;

FIG. 8 shows a special construction of a spring sleeve; and I FIG. 9shows a special construction of an expansion body.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The device according-to theinvention as shown in FIG. 1 comprises a spring sleeve I wound from wirein the manner of a block spring. A fixing screw 3 meshes with anexpansion body 2. By screwing the fixing screw 3 into the conicalexpansion body 2, the latter is drawn axially into the spring sleeve 1.The coils or convolutions at the leading end portion of the springsleeve 1 are thus widened and pushed radially outwardly against the wallof the drill hole 7 formed in a concrete support structure 8.

The expansion body 2 further has at its leading or insertion end acollar 4, the outside diameter of which corresponds to the innerdiameter of the drill hole. A cap 5 is set upon the rear or trailing endof the spring sleeve 1, having one section which protrudes into thecenter passage of the spring sleeve 1, and another section which coversthe rear end face of the spring sleeve 1. This prevents the first coilat the trailing end of the spring sleeve 1 from jamming or tilting inthe drill hole of an object 6 to be fixed to structure 8. The coils ofthe spring sleeve 1 adapt themselves to the irregular form of the drillhole 7 in the concrete support structure 8 and thus prevent by theirintrinsic tension force a twisting of the spring sleeve 1 when thedevice is fastened.

The expansion body 2 shown in FIG. 2 has at its trailing end oppositethe leading or insertion end an additional cylindrical portion orattachment 9, the outside diameter of which corresponds to the insidediameter of the spring sleeve 1. A collar 10 is arranged at the frontend of the attachment, which collar engages between the coils of thespring sleeve. This collar 10 is advantageously formed as or with athread.

In the embodiment shown in FIG. 3, the cap 5 has two sections 5a, 5b, ofwhich the section 5a protrudes into the bore of the spring sleeve 1 andthe section 5b covers the rear end face of the spring sleeve 1. Thesection 5a is conically tapered in direction towards the expansion body2. When the expansion body 2 is drawn in, the spring sleeve 1 is thusbraced between the two opposite cones of the expansion body 2 and thecap 5 by means of the fixing screw 3. The cap 5 is supported by theobject to be fixed and thus aids in preventing a withdrawal of thespring sleeve 1. I

FIG. 4 shows an embodiment in which a section 3a of the fixing screwwhich engages in the expansion body 2, in the spring sleeve 1 and in thecap 5, is set off. The outside diameter of the shaft 3b of the fixingscrew 3 corresponds to the outside diameter of the spring sleeve 1. Whenthe expansion body 2 is drawn in, the cap 5 is in this embodimentsupported by the front face 11 of the shaft 3b of the fixing screw 3. Inthis embodiment it is also possible to make the cap and the fixing screwof one piece.

The cap 5 shown in FIG. 5 is provided, as an extension of its cone withan additional cylindrical portion or attachment 12 the outside diameterof which corresponds to the inside diameter of the spring sleeve 1. Acollar 13 is arranged at the front end of the attachment and engagesbetween the coils of the spring sleeve 1. This collar is advantageouslyformed as or with a thread.

According to FIG. 6 the section 5b of the cap 5 is rearwardly extendedand serves for the support of the object 6 which is to be fixed to thesupport structure. The fact that the outside diameter is uniform overthe entire length of the device makes push-through assembly possible, inwhich the same drill hole diameter is required both in the object 6 tobe fixed and in the support structure 8.

The circumferential saw tooth-shaped recess subdivides the extendedsection 5b of the cap 5 into two parts, the length of the upper part 5ccorresponding approximately to the thickness of the object 6 to befixed. The saw tooth-shaped recess 20 serves on the one hand asknock-off notch for the upper part 5c and on the other hand as anupsetting zone which should render it possible for the fixing screw 3 tobe drawn, after the anchoring of the device is completed, in thedirection toward the surface of the structure 8 for bracing the ob ject8 between such surface and the head of screw 3.

FIG. 7 shows another construction of the recess 20, which is easier tomanufacture. In this case, the free rear end of the cap 5 is providedwith a wider bore section 23 which ensures a lower wall thickness of thecap in the zone of the rear end thereof. In the zone of the thus reducedwall thickness, the cap may give way in axial direction when an axialforce is applied, by crumpling. The section 23 may be connected with theremainder of the bore by a tapered bore section 23'.

FIG. 8 shows a special embodiment of the spring sleeve. In thenon-expanded state, the coils of the major part 22 of the spring sleeveare in immediate abutting contact with one another in the manner of ablock spring, while the coils of the remaining part 21 which faces awayfrom the expansion body 2, are spaced from one another. The cap 5 can bemoved in the direction of the expansion body 2 by the total amount ofthe distances between the coils of the smaller part 21, by deflectingthe coils thereof into abutment with one another.

In FIG. 9, the expansion body 2 has a cone 30 and at its insertion end acollar 4, the outside diameter of which corresponds to the innerdiameter of the drill hole 7. A cylindrical section 31 for taking up atleast one coil of the spring sleeve 1 is arranged between the cone 30and the collar 4. The diameter of this section 31 corresponds to thelargest diameter of the cone 30. A head screw or a stay bolt with nutmay selectively be used as the fixing screw 3,

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in ananchoring device, it is not intended to be limited to the details shown,since various modifications and structural changes may be made withoutdeparting in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. An anchoring device for use in bore holes formed in structures,particularly bore holes formed in concrete structures, comprising ahelical block-spring expansion sleeve having a leading and a trailingopen axial end; discrete internally threaded expander member located atsaid leading axial end and including a substantially cylindrical firstportion located exteriorly of said leading axial end and having ashoulder with an outer diameter greater than the inner diameter of saidspring sleeve, a second portion located in said leading axial end andconverging in direction toward said trailing axial end, and acylindrical intermediate third portion located between said first andsecond portions and having an axial diameter equalling the maximum outerdiameter of said second portion, and an axial length corresponding tothe axial length of at least one convolution of said spring sleeve;threaded expanding means extending from said trailing axial end throughsaid spring sleeve into threaded engagement with said expander memberand being operable for advancing the latter in direction toward saidtrailing axial end to thereby effect radial expansion of said springsleeve; and a discrete cap member at said trailing axial end andprovided with an axial passage through which said expanding meansextends, said cap member including a first section located within saidtrailing axial end'and a second section axially abutting said trailingaxial end.

5. A device as defined in claim 1, said second portion of said expandermember having an end region remote from said first portion and being ofcylindrical configuration, said end region having an outer diametercorresponding to the inner diameter of said spring sleeve.

6. A device as defined in claim 5; and further comprising an outwardlyprojecting collar provided on said end region and adapted for engagementbetween respective adjacent convolutions of said spring sleeve.

7. A device as defined in claim 1, said expanding means comprising anelongated threaded bolt having a leading portion of smaller diameterreceived in said spring sleeve, and a trailing portion located outsidesaid trailing end of said spring sleeve and being of a diametercorresponding to the diameter of said spring sleeve in non-expandedcondition.

8. A device as defined in claim 1, wherein said first section of saidcap member converges in direction to wards said leading end of saidspring sleeve.

9. A device as defined in claim 1, wherein said first section of saidcap member includes a leading end portion of cylindrical configurationand having an outer diameter corresponding to the inner diameter of saidspring sleeve, and an intermediate portion connecting said leading endportion with said second section and converging in direction from thelatter towards the former.

10. A device as defined in claim 9, said leading end portion includingan outwardly extending collar portion arranged to engage betweenadjacent convolutions of said spring sleeve.

11. A device as defined in claim 1, said spring sleeve having a longerfirst sleeve section extending from said leading toward said trailingend, and a shorter second sleeve section extending from said firstsleeve section to said trailing end; and wherein adjacent convolutionsin said first sleeve section are in abutment in nonexpanded state ofsaid spring sleeve, and adjacent convolutions in said second sleevesection are spaced from one another.

12. A device as defined in claim 1, said second section having atrailing endface remote from said first section; and wherein said axialpassage has a widened passage portion extending from saidtrailingendface towards said first section.

13. An anchoring device for use in bore holes formed in structures,particularly bore holes formed in concrete structures, comprising ahelical block-spring sleeve having a leading and a trailing open axialend; an expander member located at said leading axial end and includingan annular first portion located exteriorly of said leading axial endand having an outer diameter at least equal to that of said springsleeve, a second portion located in said leading axial end andconverging in direction towards said trailing axial end, and acylindrical intermediate third portion located between said first andsecond portions and having an outer diameter equalling the maximum outerdiameter of said second portion and an axial length corresponding to theaxial length of at least one convolution of said spring sleeve;expanding means extending from said trailing axial end into engagementwith said expander member and being operable for advancing the latter indirection towards said trailing axial end to thereby effect radialexpansion of said spring sleeve; a cap member at said trailing axial endand provided with an axial passage, said cap member including a firstsection located within said trailing axial end and a second sectionaxially abutting said trailing axial end, said second section having anouter circumferential surface and a trailing endface remote from saidfirst section; and a circumferential groove formed in said outercircumferential surface intermediate said trailing endface and saidfirst section.

14. A device as defined in claim 13, wherein said groove is ofsubstantially sawtooth-shaped crosssection.

15. A device as defined in claim 13, wherein said groove is spaced fromsaid trailing endface by a distance which is selected to correspond tothe thickness of a component which is to be connected to a structure,

via said device.

1. An anchoring device for use in bore holes formed in structures,particularly bore holes formed in concrete structures, comprising ahelical block-spring expansion sleeve having a leading and a trailingopen axial end; discrete internally threaded expander mEmber located atsaid leading axial end and including a substantially cylindrical firstportion located exteriorly of said leading axial end and having ashoulder with an outer diameter greater than the inner diameter of saidspring sleeve, a second portion located in said leading axial end andconverging in direction toward said trailing axial end, and acylindrical intermediate third portion located between said first andsecond portions and having an axial diameter equalling the maximum outerdiameter of said second portion, and an axial length corresponding tothe axial length of at least one convolution of said spring sleeve;threaded expanding means extending from said trailing axial end throughsaid spring sleeve into threaded engagement with said expander memberand being operable for advancing the latter in direction toward saidtrailing axial end to thereby effect radial expansion of said springsleeve; and a discrete cap member at said trailing axial end andprovided with an axial passage through which said expanding meansextends, said cap member including a first section located within saidtrailing axial end and a second section axially abutting said trailingaxial end.
 2. A device as defined in claim 1, wherein said expandingmeans is an elongated threaded member.
 3. A device as defined in claim1, wherein said spring sleeve is of soft metallic wire.
 4. A device asdefined in claim 1, wherein said spring sleeve is of copper wire.
 5. Adevice as defined in claim 1, said second portion of said expandermember having an end region remote from said first portion and being ofcylindrical configuration, said end region having an outer diametercorresponding to the inner diameter of said spring sleeve.
 6. A deviceas defined in claim 5; and further comprising an outwardly projectingcollar provided on said end region and adapted for engagement betweenrespective adjacent convolutions of said spring sleeve.
 7. A device asdefined in claim 1, said expanding means comprising an elongatedthreaded bolt having a leading portion of smaller diameter received insaid spring sleeve, and a trailing portion located outside said trailingend of said spring sleeve and being of a diameter corresponding to thediameter of said spring sleeve in non-expanded condition.
 8. A device asdefined in claim 1, wherein said first section of said cap memberconverges in direction towards said leading end of said spring sleeve.9. A device as defined in claim 1, wherein said first section of saidcap member includes a leading end portion of cylindrical configurationand having an outer diameter corresponding to the inner diameter of saidspring sleeve, and an intermediate portion connecting said leading endportion with said second section and converging in direction from thelatter towards the former.
 10. A device as defined in claim 9, saidleading end portion including an outwardly extending collar portionarranged to engage between adjacent convolutions of said spring sleeve.11. A device as defined in claim 1, said spring sleeve having a longerfirst sleeve section extending from said leading toward said trailingend, and a shorter second sleeve section extending from said firstsleeve section to said trailing end; and wherein adjacent convolutionsin said first sleeve section are in abutment in non-expanded state ofsaid spring sleeve, and adjacent convolutions in said second sleevesection are spaced from one another.
 12. A device as defined in claim 1,said second section having a trailing endface remote from said firstsection; and wherein said axial passage has a widened passage portionextending from said trailing surface towards said first section.
 13. Ananchoring device for use in bore holes formed in structures,particularly bore holes formed in concrete structures, comprising ahelical block-spring sleeve having a leading and a trailing open axialend; an expander member located at said leading axial End and includingan annular first portion located exteriorly of said leading axial endand having an outer diameter at least equal to that of said springsleeve, a second portion located in said leading axial end andconverging in direction towards said trailing axial end, and acylindrical intermediate third portion located between said first andsecond portions and having an outer diameter equalling the maximum outerdiameter of said second portion and an axial length corresponding to theaxial length of at least one convolution of said spring sleeve;expanding means extending from said trailing axial end into engagementwith said expander member and being operable for advancing the latter indirection towards said trailing axial end to thereby effect radialexpansion of said spring sleeve; a cap member at said trailing axial endand provided with an axial passage, said cap member including a firstsection located within said trailing axial end and a second sectionaxially abutting said trailing axial end, said second section having anouter circumferential surface and a trailing endface remote from saidfirst section; and a circumferential groove formed in said outercircumferential surface intermediate said trailing endface and saidfirst section.
 14. A device as defined in claim 13, wherein said grooveis of substantially sawtooth-shaped cross-section.
 15. A device asdefined in claim 13, wherein said groove is spaced from said trailingendface by a distance which is selected to correspond to the thicknessof a component which is to be connected to a structure, via said device.